Why impose any metal on anyone? Why not just let banks accept any standardised commodity they want as specie? This only works if fractional reserve banking is abolished and this is a privately controlled currency with legal competition. There need not be chaos thanks to debit cards that could be used for all transactions. Government could still set a standard by which a price would be fixed (not of any actual currency, but so that people knew the relative value) so that retailers would only have to post one price. Also, as long as it's unaffiliated with the government and there's no fractional reserve banking, fiat currencies like Bitcoin might be competitive as well. Ron Paul never spoke ill of private fiat currencies, but most Austrian economists don't believe that fiat currencies would be competitive in a free market so he probably never thought it worth mentioning.